Moonstar AKA Winza or Rehau UPVC what a dissapointment

In 2017 I have installed UPVC windows and doors via Moonstar now known as Winza.These items were fitted with integrated blinds between the double glasing and I was assured that this installation comes with an unqualified 15 year guarentee.The aforementioned is misleading as their aftersales service is apauling and non-existant and in the light of the fact that all their products (Rehau) is imported from Istanbul it makes repairs unaffordable and impossible to come by.Rehau South Africa is equally non responsive.Do not use this Company or products!!!!!!!